The Hawaii government may soon be requiring COVID-19 booster shots for all travelers from other U.S. states. Under the proposed rule, only those who have received a third shot will be allowed to travel to the islands without having to quarantine or submit to further COVID-19 testing.

Hawaii Governor David Ige said that they are considering implementing new rules that would change the definition of "fully vaccinated" travelers. With the proposed change, the definition would only apply to those who have received three doses instead of just the regular two vaccine doses.

Domestic travelers who aren't "fully vaccinated" under the new rules will have to be tested for COVID-19 before and after arrival. They would also be required to isolate for up to five days upon arrival at their own expense.

For now, U.S. travelers with proof of vaccination - two COVID-19 shots - do not have to be tested or quarantined. Unvaccinated travelers still need to get tested and come out with a negative result to bypass mandatory quarantine. Travelers from outside the U.S., even those fully vaccinated, still need to follow standard testing requirements under the country's broader travel restrictions.

Hawaii implements a proof of vaccination system under its Safe Travels program. Under the program, travelers can upload their proof of vaccination online ahead of their flights for ease of use and quick reference.

Ige said that if Hawaii does opt to implement the rule changes, it would be giving travelers at least a two-week notice so they will have enough time to get their booster shots. He acknowledged that travelers would need some time to react to the changes, particularly those who had already booked trips to the islands.

Ige said his office is in contact with local hospitality partners throughout the islands about the idea of mandating booster injections for those who attend public events and gatherings. The Centers for Disease Control and Prevention (CDC) currently has no recommendations on whether booster shots should be necessary for foreign or domestic travel.

Outside of the U.S., some countries are starting to mandate COVID-19 booster shots for both residents and travelers. Singapore announced earlier in the month that it would soon be requiring all eligible citizens to get booster shots, particularly those who received their second dose more than 270 days ago. Only those who had received booster shots are considered to be "fully vaccinated" in Singapore.

Thanks to its remote location and quick response, Hawaii has had a relatively low number of cases since the start of the pandemic. As of this month, the islands only reported a total of 166,008 cases and 1,123 deaths.